Sprint Mechanics and Hamstring Injury: What Athletes and Therapists Need to Know

In high-speed sports like football, sprinting is inevitable—and so are the injuries that come with it. Hamstring strains remain one of the most common and recurring injuries in football, often sidelining athletes for weeks and increasing the risk of re-injury dramatically. But why do these injuries keep happening, and more importantly, what can we do about them?

A recent review by Dr. Michael Reiman, published through Physio Network, sheds light on the relationship between sprint mechanics and hamstring injury. At RISE, we believe that understanding this connection is not just academic—it’s practical. It can mean the difference between staying on the field or watching from the sidelines.

In this blog, we’ll break down:

• The biomechanics of sprinting and how they relate to hamstring function

• Specific phases of running most associated with injury

• Key modifiable risk factors

• What physical therapists and athletes should focus on in both rehab and performance training

Understanding Sprint Mechanics

To grasp how hamstring injuries occur, we need to understand the sprint cycle and what demands it places on the body.

Sprint Cycle Breakdown

Sprinting is broken down into two main phases:

1. Stance Phase (support)

2. Swing Phase (recovery and preparation)

   
   

The swing phase is where most hamstring injuries occur—especially during the late swing phase. This is the moment just before foot strike, where the leg is fully extended forward and the hamstring is under high tension.

The Role of the Hamstrings in Sprinting

The hamstrings (biceps femoris, semitendinosus, and semimembranosus) have a dual role:

• Knee flexion: Bending the knee during recovery

• Hip extension: Driving the thigh back during the stance phase

During the late swing phase:

• The hamstrings are eccentrically contracting.

• They decelerate the forward-moving lower leg while simultaneously preparing for ground contact.

• Peak muscle-tendon unit strain occurs, especially at the long head of the biceps femoris.

This high eccentric load, combined with rapid lengthening, is the perfect storm for injury if mechanics are off.

Sprint Mechanics and Injury Risk

Dr. Reiman’s review highlights several key mechanical and neuromuscular contributors to hamstring injury risk during sprinting:

1. Overstriding

Athletes who land with the foot too far in front of their center of mass are at higher risk. Overstriding increases braking forces and places greater eccentric strain on the hamstrings.

Therapeutic Focus:

• Cue shorter, faster steps (higher cadence)

• Emphasize ground contact under the hips

• Use drills like “A-skips” and high knees to reinforce upright posture and cadence

2. Poor Pelvic Control

Anterior pelvic tilt during sprinting lengthens the hamstrings even further, especially the biceps femoris. Combine this with weak core or gluteal control, and you're looking at compromised hip extension mechanics and overloaded hamstrings.

Therapeutic Focus:

• Core strengthening (especially deep stabilizers like the transverse abdominis)

• Glute activation drills

• Hip mobility work (especially for hip flexor tightness)

3. Lumbopelvic and Trunk Stability

Inadequate trunk control leads to increased compensatory patterns. This causes altered force transmission and poor coordination between hip and knee motion, increasing the load on the hamstrings.

Therapeutic Focus:

• Anti-rotation core exercises (e.g., Pallof presses)

• Dynamic single-leg stability drills

• Sprint-specific trunk control (e.g., resisted sprint marching)

Physiological Risk Factors: Beyond the Mechanics

1. Muscle Architecture

• Fascicle Length: Shorter fascicle length in the biceps femoris long head is correlated with a higher injury risk.

• Pennation Angle and Muscle Volume: Reduced muscle size and altered architecture compromise force production and load tolerance.

Best Practice Interventions:

• Nordic hamstring curls: Proven to increase fascicle length and reduce injury rates.

• Eccentric isokinetic training: Improves tendon stiffness and load tolerance.

2. Fatigue and Neuromuscular Timing

Fatigue reduces neuromuscular coordination and delays hamstring activation timing during sprinting. This “lag” can lead to missed force absorption and subsequent overload.

Rehab Implications:

• Progressive sprint endurance work (e.g., repeat sprint training)

• Emphasize end-of-practice or fatigued-state drills to simulate game conditions

Addressing the Re-Injury Problem

Re-injury rates for hamstring strains can be as high as 30%. Why?

Common Mistakes:

• Return to play based on time, not function

• Incomplete strength recovery (especially eccentric strength)

• Poor reintegration of sprinting mechanics into training

Our Approach at RISE:

• Phase-based rehab progression

• Criterion-based return to sprinting

• Movement screening under speed and fatigue

Physical Therapy Best Practices: Hamstring Rehab Must Include Sprint Mechanics

A robust rehab and injury prevention program must go beyond isolated hamstring strengthening. Here's how we approach it at RISE:

1. Restore Eccentric Hamstring Strength

Nordic hamstring curls are the gold standard. But we also include:

• Romanian deadlifts

• Slider leg curls

• Single-leg hip hinges with eccentric bias

2. Optimize Sprint Mechanics Gradually

We teach athletes to:

• Avoid overstriding

• Increase cadence

• Maintain neutral pelvis during sprinting

We start with slow-motion video analysis, then integrate progressive sprint drills like:

• Wall drills

• Resisted sprint marches

• Band-resisted sprints

3. Train the Whole Posterior Chain

The hamstrings rarely fail in isolation. A weak glute or stiff lumbar spine can cascade into compensatory loading. We prioritize:

• Glute max and med strengthening

• Thoracic mobility

• Ankle and foot strength (to support push-off)

4. Include Plyometrics and Elastic Training

Plyometric drills mimic the stretch-shortening cycle demands of sprinting. We incorporate:

• Bounding

• Hurdle hops

• Depth drops with sprint transitions

These train the neuromuscular system to handle high rates of loading—essential for preventing sprint-related injuries.

5. Integrate Sport-Specific Sprinting

Hamstring rehab shouldn’t end with treadmill jogging. We build in:

• Position-specific sprint drills

• Direction changes

• Deceleration and re-acceleration under load

Our return-to-play checklist includes:

• 95%+ eccentric strength compared to contralateral limb

• Pain-free full-speed sprinting

• No compensation or pelvic drop on video analysis

• High-speed sprint exposures (>90% max velocity) repeated over multiple sessions

Prevention Starts With Education

Athletes, coaches, and parents must understand:

• Why sprint mechanics matter

• How to train the hamstrings in a functional way

• That not all hamstring injuries are created equal

We hold workshops and video analysis sessions with local teams to educate on:

• Proper warm-ups

• Sprint technique

• Load management

Key Takeaways

• Hamstring injuries often occur during the late swing phase of sprinting, where eccentric demands are highest.

• Overstriding, pelvic tilt, and poor trunk control significantly increase injury risk.

• Eccentric strength training (especially Nordic curls) is crucial—but must be paired with sprint-specific movement re-training.

• High re-injury rates are preventable with a well-structured, mechanics-informed return-to-play progression.

Ready to Sprint Smarter?

At RISE, we specialize in blending movement science with real-world sport demands. If you or your athlete is dealing with a hamstring injury—or just wants to prevent one—schedule a sprint assessment with us. We’ll break down your form, identify risk factors, and design a plan that gets you sprinting faster and safer than ever.